For what it’s worth, I’ve never heard the user that Hixie is alluding to refer to themselves as an “accessibility expert.” However, I would in fact label this person exactly that. He has been invaluable at testing and implementing solutions for accessibility issues in Drupal community. He has been especially helpful with 508 accessibility issues we have encountered. Despite having a team of “accessibility experts” at my disposal (we take accessibility very seriously at San Francisco State University, indeed we won the Digital Inclusion award in '08 http://www.sfsu.edu/~news/prsrelea/fy08/026.html), I have often turned to this person for advice.
Regardless of the outcome of the original issue, the behavior of Ian Hixie in this matter is out-of-line at best and discriminatory at worst. Issues should be figured out based on the facts at hand and potential implementation, not by ad hominem attacks towards a person’s character. For shame.